- Matt Bomer - Bruce Wayne/Batman, a millionaire playboy who, on the anniversary of his parents' deaths, decides to fight crime to avenge his parents' deaths. He dresses up as a bat to strike fear into his enemies, and is dubbed "the Batman" by the media.
- Shawn Ashmore - Dick Gayson, an employee at Wayne Enterprizes who befriends Bruce Wayne.
- Willem Dafoe - Roman Sionis , the C.E.O of Sionis Industries, rival company of Wayne Enterprizes. He despises Bruce more than anything else.
- William H. Macy - Jim Gordon, the commissioner of the GCPD who at first wants to unmask the Batman, but eventually befriends him.
- Lynn Collins - Silver St. Cloud, Bruce Wayne's girlfriend who falls for the Batman after being saved by him.
- Christoph Waltz - Maximillian "Maxie" Zeus, the rich owner of the nightclub known as the Gotham Olympus. He is obsessed with Greek mythology and believes he is the reincarnation of Zeus. His goal is to take over Gotham City, which he sees as Mount Olympus.
- Norman Reedus - Garfield Lynns/Firefly, a former firefighter who became a pyromaniac after nearly dying in a fire. He begins to believe that fire is the "one true meaning of life" and everything must burn. He becomes the masked arsonist known as "Firefly" and starts wreaking havoc through Gotham.
- Tobin Bell - Alfred Pennyworth, Bruce Wayne's butler who made a promise to protect him ever since his parents died.
- Jackie Earle Haley - Joe Chill, a mugger who murdered Bruce Wayne's parents thirty years ago.
- Jon Hamm - Thomas Wayne, Bruce Wayne's father who was murdered by Joe Chill.
- Gwyneth Paltrow - Martha Wayne, Bruce Wayne's mother who was murdered by Joe Chill.
The film starts at a party. Bruce Wayne is standing on the balcony, looking down upon the city. His girlfriend, Silver St. Cloud, asks him what's wrong, and he says that tonight is the anniversary of the night his parents died. Thirty years ago, a young Bruce and his parents were at the Monarch Theater when Bruce got scared and asked if they could go home. While walking out of the theater, they are mugged by a man named Joe Chill. Joe tells Bruce's mother Martha to hand over her necklace. Bruce's father Thomas tells Joe he is going to call the police, when Joe pulls out a gun and shoots Thomas. Martha screams, and is shot by Joe. Joe runs off with Martha's necklace and Thomas' wallet, leaving behind a scared Bruce. Back in the present, Bruce leaves the party and goes back to Wayne Manor, where he tells his butler Alfred that nobody else should ever have to go through what he went through. A bat suddenly flies into the house, crashing through the window. Bruce is startled by it, and goes to see where it came from. In the woods not too far from Wayne Manor, Bruce and Alfred find a cave full of bats. Bruce wanders into the cave, and discovers a tunnel that leads down into a hidden empty area. That night, Bruce stays up designing a costume. The costume is modeled after a bat, to strike fear into criminals. He shows it to Alfred and says he wants to become a crime-fighter so he can bring law-breakers like Joe Chill to justice.
Meanwhile, at Sionis Industries, Roman Sionis tells his secretary that tonight is the anniversary of the night that his long-time business rival Thomas Wayne died. Roman says it was a wonderful night for him, though he couldn't help but feel sorry for Thomas' son. Sionis tells his secretary it's time for the "meeting", so he has to go. In the basement of the building, Sionis meets with Maximillian "Maxie" Zeus, a rich night club owner. Maxie and Roman discuss their plan about turning Sionis Industries into Zeus-Sionis Industries, which Roman hopes will do good for business.
Later on that night, Bruce and Alfred begin making a bulletproof bat-like suit based off of Bruce's design. The next day at Wayne Enterprizes, Bruce is in his office, working on designs for his bat suit, when he gets a call from Silver St. Cloud. Silver asks if he's okay, and Bruce says that everything's fine, but he's working on a special project right now and he has to hang up. Silver is beginning to worry about him, because he seems to be very busy all the time. Bruce finishes the suit and then starts working on weapons for his war against crime. He finishes and tests out a grappling gun, which doesn't work too well. Later that night, Bruce and Silver are at another party, where Bruce runs into Dick Grayson, who he recognizes because Grayson is an employee at Wayne Enterprizes. Grayson and Bruce begin to talk and become good friends. Bruce finds out Dick is an orphan, too. When Bruce and Silver are leaving the party, Bruce sees a man getting mugged. Despite Silver telling him he should just call the police because it is too dangerous, Bruce rushes to help. Bruce threatens to call the police, and the muggers run off. At Wayne Manor, Bruce tells Alfred about the whole thing and says he is ready to start his war against crime.
Meanwhile, a local hotel is on fire, and several firefighters have arrived. Garfield Lynns, who is one of Gotham's "best" firefighters, rushes into the hotel to rescue some civilians who are stuck inside. He grabs a young girl stuck in a hotel room and rushes out as the room fills up with burning debris. A piece of burningdebris falls down through the ceiling and lands on Garfield, setting him on fire. Some other firefighters arrive and help out. One brings the little girl outside to safety while the other rescues Garfield. Garfield survives the whole thing, but is severely injured. Garfield is brought to the hospital, where he stays for a while. He begins to descend into madness, becoming obsessed with fire. He starts to believe that fire is the one true meaning of life. When he gets out of the hospital, he starts working on a fireproof suit. He adds built-in flamethrowers to the suit and begins wreaking havoc at night. Every night, he goes out into the city and burns down buildings, believing it is for the "greater good". The press dubs this masked arsonist "the Firefly".
Patrolling the town in his new suit, Bruce sees some criminals robbing a bank. Trying to be as stealthy as possible, he makes his way into the bank unnoticed, takes out all the robbers one by one, puts the money back, and escapes just before the police arrive. Comissioner Jim Gordon asks one of the robbers what happened, and the robber says "a monster wearing a bat mask came and attacked me!" Gordon is confused, and thinks that the robbers must be drug addicts. The next day, Silver calls Bruce and tells him that she heard a crazy story in the news about a giant bat that stopped a robbery. Bruce notices that everyone seems to be fascinated by this story, besides the authorities, who think of this new hero as an anarchist punk.
At the Gotham Olympus, Roman shows up and tells Maxie that the club is in danger. Roman explains that a new masked arsonist, the Firefly, has been destroying local buildings lately, and the police have detected some sort of pattern. Roman says that if he keeps going by the pattern, that the Olympus is next. Maxie, afraid of losing the Olympus, hires several armed mercenaries to guard the club. Later that night, Firefly arrives. He sneaks past the mercenaries, and into the club. He is about to start destroying the building when the mercenaries break in. Firefly grabs a grenade and throws it into the group of mercenaries coming at him. A mercenary sneaks up and attempts to grab him from behind, but he quickly ducks down, turns around, and sets the mercenary on fire. The building begins to catch fire, and the whole place burns down. Firefly gets out alive thanks to his suit and escapes. Zeus is devastated to find out the Olympus has been destroyed, and puts a fifty-hundred dollar bounty on Firefly's head.
Commissioner Gordon is investigating the mystery of the Batman, and goes to Wayne Manor after finding a bat-shaped steel boomerang at the scene of the crime. He thinks it may have been made at Wayne Enterprizes and questions Bruce about it. Bruce says he doesn't have time for the interrogation because he has a date with Silver St. Cloud, but Gordon won't go away. Bruce tells Gordon he doesn't know anything about the batarang, and eventually Gordon leaves. Bruce leaves for his date with Silver, but sees something suspicious going on. He investigates it in his batsuit, and discovers that the suspicious people are actually assassins going to a factory to meet with Maxie Zeus. After spying on their conversation, Bruce discovers that Zeus is hiring the assassins to kill somebody, though he doesn't know who. Bruce attacks Zeus and the assassins, but is outnumbered. He throws a small pellet to the ground that releases a cloud of smoke. The assassins, unable to see him, are easily defeated by Bruce. Bruce finds out that Zeus and his thugs get away while he fought the assassins.
The next day, Dick walks into Bruce's office to talk to him, and Dick says he found some blueprints while looking around. They are blueprints for a heavily-armed bulletproof vehicle. Bruce tries to change the subject, but it isn't easy. Bruce and Dick are interrupted when Alfred walks in and shows Bruce a newspaper article. The article is another one about the "Bat-Man". Bruce tells Dick to leave, and after Dick leaves, Alfred tells Bruce he's worried he might blow his cover and get arrested. Alfred wants Bruce to stop fighting crime, but Bruce says that the city needs a hero.
A sequel, Batman: City At War, has been announced. Matt Bomer, Shawn Ashmore, Tobin Bell, Lynn Collins, Willem Dafoe, and William H. Macy will reprise their roles as Batman, Dick Grayson, Alfred Pennyworth, Silver St. Cloud, Roman Sionis, and Jim Gordon, and Anna Kendrick and Matt Damon will play Barbara Gordon and Harvey Dent. Also, Joseph Gilgun and Richard Dorton have been casted in currently unknown roles.